In Wilmington, North Carolina, a stray cat is chased by a dog. When it hides inside a shipping truck, the cat becomes a stowaway as the truck travels to New York City. Upon getting out of the truck on the busy streets of Manhattan, the cat sees a mannequin in a store window, and psychically hears the voice of a little girl asking for its help, saying that something is after her. However, the cat is captured by an unknown man. Elsewhere in the city, a man named Jim drops off his friend, Dick Morrison, at “Quitters, Inc.,” a “stop smoking” clinic. Dick is taken aback by clinic owner Dr. Donatti’s radical methods. Donatti opens a curtain to reveal the stray cat behind a window, and placed in a room with a wire floor. Donatti electrifies the floor, shocking the cat, and threatens to do the same to Dick’s wife, Cindy, if he smokes another cigarette. After a second relapse, Donatti asserts that Dick's daughter, Felicia, will face the shocks, and after a third offense, he threatens to send men to rape Dick’s wife. He flashes a gun, implying the final punishment. Later that night, Dick sneaks a cigarette, but before he lights it, he hears noises in his closet, and believing someone is hidden inside, breaks the cigarette in half and returns to bed. The next morning, he sees footprints coming from the closet, and vows never to smoke again. When Dick visits Felicia at Saint Stephen’s School for the Exceptional, Donatti follows, and promises Dick that he will keep intensive scrutiny on him for a month. Two weeks later, Dick attends a party where everyone is smoking, and although the temptation is overwhelming, he resists the urge to smoke. In time, Dick finds a pack of cigarettes in his automobile, and gives in to temptation. As he inhales, he sees a man watching him. Dick races home to find his wife, Cindy, missing, and receives a telephone call from Donatti, requesting Dick come to his office. True to his word, Donatti has Cindy locked in the cage. Dick tries to break the glass, but Donatti’s henchman holds him at gunpoint. In the struggle, the cat escapes and makes its way out of the building. Dick watches in horror as Cindy’s feet are electrocuted and she leaps around screaming. Afterward, Dick apologizes to his wife, and she forgives him. Meanwhile, the cat boards a freighter, and leaves the city. In time, Dick successfully quits smoking. He leaves Dr. Donatti’s office with a prescription for weight loss pills, and Donatti jokes that he will cut off Cindy’s pinky finger if Dick fails to take them. Later, Dick and Cindy have dinner with Jim and his wife, Sally Ann, and they toast Quitter’s, Inc. As Sally Ann raises her glass, Dick sees that part of her pinky finger is missing. In time, the cat arrives on the shores of Atlantic City, New Jersey, and hears another message from the little girl seeking its help. Outside a casino, the cat is nearly hit while crossing the street, and a high-roller named Cressner bets an employee that the cat will make it safely across the busy street. When it does, Cressner picks up the cat to take it home, but first gets assurance from his henchman that the hit he ordered on his wife and her lover will be carried out by a thug named Ducky. Elsewhere, John Norris puts Cressner’s wife, Marcia, on a bus headed for New York City, and promises to meet her there later. John Norris is attacked by Ducky, and taken to Cressner, who has another thug plant heroin in John’s automobile. Cressner threatens to alert police and have John arrested for drug possession if he does not reveal Marcia’s whereabouts. However, Cressner offers John a wager that could allow him to be with Marcia and receive a large sum of money. He challenges John to walk the length of the narrow ledge that surrounds his penthouse apartment. Reluctantly, John accepts. Cressner and Ducky try their best to make John fall, but after a harrowing ordeal, John succeeds. As the cat looks on, Cressner gives John a bag containing Marcia’s severed head, and tries to shoot John. However, John gets hold of the gun, and forces Cressner to walk the ledge himself. Cressner falls to his death. Meanwhile, the cat escapes again, and boards a train bound for Wilmington, North Carolina. The cat follows an unseen menace inside the home of a little girl named Amanda, who pleads with her mother to keep the cat. Her mother relents, but will not allow “General” to sleep in the house. Amanda continues to plead with her mother to allow the cat to sleep with her, and explains to her father, Hugh, that General keeps away her recurring nightmares about the monster living in her wall. While Amanda sleeps, the pint-sized monster emerges, and kills her pet bird, Polly. As the creature descends upon the sleeping girl, wielding a knife, General jumps through the open window to protect her. The monster stabs General, and retreats into the wall. The ruckus awakens the family, and Amanda shrieks when she finds Polly dead. She blames the monster, but her mother accuses General, noting the trail of blood on the windowsill. In the morning, Hugh notices the bloody wound on General’s shoulder, and tells his wife, but her dislike of the cat persists. After everyone leaves, Amanda’s mother lures the cat into a trap, and takes it to a shelter. Sometime later, a storm brews, and Amanda goes outside to search for General, who is set to be exterminated the following day. That night, as the monster reemerges, General escapes from the shelter and races through the rain to Amanda’s rescue. The small ghoul steals Amanda’s breath, but General arrives and fights the creature. Her parents hear Amanda’s screams, but the monster has blocked the door and they cannot get inside her bedroom. General chases the knife-wielding creature around the room, as Amanda cheers him on. When the monster jumps onto a record player, General speeds up the rotation, and the ghoul is flung into a fan and killed. Her parents finally break the door open, and Amanda’s mother is furious to see General. However, Amanda tells them about the monster, and they finally believe her when they see its mutilated body parts around the fan. Her mother makes Amanda promise not to tell anyone about the monster, and Amanda blackmails her mother into letting her keep General.